A study of the dynamic damage characteristics of Rock-Like materials with different connectivity of concealed structural surfaces. (October 2022)

• Record Type: Journal Article
• Authors: Liu, Liansheng; Yang, Yan; Chai, Yaoguang; Zhong, Shuliang; Chen, Hao; Xia, Shengming; Tao, Tiejun
• Is Part Of: Theoretical and applied fracture mechanics. Volume 121(2022)
• Publication Date: 2022-10
• Subjects: Concealed structural surfaces -- Structural surface connectivity -- Similarity simulations -- Failure characteristics -- Dynamic compressive strength -- ANSYS/DYNA; Fracture mechanics -- Periodicals; 620.1126
• DOI: 10.1016/j.tafmec.2022.103497
• Languages: English
• ISSNs: 0167-8442

Abstract

Highlights: In this work, similar simulated materials were used to produce specimens with concealed structural surfaces at different connectivity. An improved SHPB experimental system was combined with finite element software ANSYS/LS-DYNA for the purpose of analyzing the influencing effects of the connectivity of the concealed structure surfaces on the dynamic mechanical property, and damage characteristics of the specimens, and the fracture evolution pattern of the specimen was obtained. There are some new findings: The stress–strain curve of the specimen with a concealed structure appeared as "stress bimodality." This phenomenon was determined to be related to the structural surface connectivity and impact velocity of the specimen. In addition to tensile cracks, vertical arc-shaped shear cracks also appeared in the failure mode of specimens with concealed structural surfaces. Moreover, the order of the appearance of the tensile cracks and compression-shear cracks, as well as the sizes of the cracks, were determined to be closely related to the structural surface connectivity. The results in this study were considered to have both theoretical and practical significance for the safe engineering evaluations of rock masses. Abstract: In order to explore the dynamic mechanical properties and failure laws of rock masses with different connectivity of concealed structural surfaces, this study used rock-like materials to produce specimens with concealed structural surfaces at different connectivity levels. An improved Separated Hopkinson Pressure Bar (SHPB) experimental system was applied in combination with the finite element software ANSYS/LS-DYNA. Then, the dynamic properties, energy transfer laws, and failure characteristics of the concealed structures with different connectivity were analyzed. The research results showed that the peak stress and yield stress level of the specimen gradually decreasedas connectivity parameter increases. However, it was observed that the average strain rate continued to increase with the increased connectivity of the structural surface under the same impact velocity. The stress–strain curve of the specimen with a concealed structure appeared as "stress bimodality." This phenomenon was determined to be related to the structural surface connectivity and impact velocity of the specimen. In addition, the specimen's energy absorption rate first increased and then decreased with the increases in the structural surface connectivity. It was found that the reflection coefficient gradually increased, and the transmission coefficient exhibited a negative linear relationship with the connectivity of the structural surface. In addition to tensile cracks, vertical arc-shaped shear cracks also appeared in the failure mode of specimens with concealed structural surfaces. Moreover, the order of the appearance of the tensile cracks and compression-shear cracks, as well as the sizes of the cracks, were determined to be closely related to the structural surface connectivity. This study's research results also revealed the deformation and failure laws and energy evolution characteristics of the rock-like materials with different concealed structural surface connectivity under different velocity impact loads.